A New Operation Method of Relay Protection Hardwarewith VFC Pulse Train as Variable

Abstract

[Introduction] In the basic theory of digital signal processing, the calculus operation of continuous time variable function can be transformed into the difference and accumulation operation of corresponding discrete signal.At present, the application of this principle in microcomputer type relay protection is based on the software operation of fixed interval sampling value.In this paper, A new application type of the above theory is proposed, which integrates the sampling and operation process into the discrete, quantization and coding links of A/D conversion, so as to simplify the computational overhead and improve the protection performance. [Methods] The real-time sequence and delay sequence of VFC serial pulse signal were taken as variables, the counter was taken as the core computing hardware, and the single and multiple "floating operation Windows" were constructed with pulse delay devices to realize the hardware synchronization of calculus and phasor addition and subtraction.Based on the mature theory of software protection algorithm, the new algorithm formula is obtained by interval transformation and the loop construction mode is proposed. [Result] After discussion and calculation, the following results are obtained. The new method can be used to construct the instantaneous integral value of the electrical quantity, the instantaneous sampling value and the effective value of the definite integral. [Conclusion] Although the operation is based on the same basic principle as software operation, the physical process of operation is very simple, which can complete high-precision synchronous operation, and form a variety of operators, which can construct a protection scheme of multiple principles.

Keywords

• microcomputer protection algorithm
• pulse train
• floating window
• counter
• vfc